LINKING SCIENCE TO MANNED SPACE FLIGHT

Manned Space Flight and Science

When the engineers of Robert R. Gilruth's Space Task Group began work on
Project Mercury in 1958, they could not - as the space scientists could
- draw on 10 years of experience in designing their spacecraft and
conducting their missions. Aviation experience was helpful in some
aspects of manned space flight, but in many others they faced new
problems. Apollo posed many more. The engineers did not lack confidence
that the President's goal could be met, but they knew only too well how
much they had to learn to achieve it. A sense of urgency pervaded the
manned space flight program from the beginning right up to the return of
Apollo 11 - an urgency that determined priorities for engineers at the
centers. Every ounce of effort went into rocket and spacecraft
development and operations planning. Science was considerably farther
down the list, and for the first five years they gave it little thought.

Manned space flight projects were ruled by constraints that were less
important to science projects. One was safety. Space flight was a risky
business, obviously, but the risks had to be minimized. No matter that
the astronauts themselves (all experienced test pilots in the beginning,
accustomed to taking risks) understood and accepted the risks. From the
administrator down to the rank-and-file engineer, everyone knew that the
loss of an astronaut's life could mean indefinite postponement of man's
venture into space. Moreover, NASA was in a race, competing against a
competent adversary and working in the public eye, where its failures as
well as its successes were immediately and widely publicized.

Reliability was one key to safety, and spacecraft engineers strove for
reliability by design and by testing. With few exceptions, critical
systems - those that could endanger mission success or crew safety if
they failed - were duplicated. If redundancy was not feasible, systems
were built with the best available parts under strict quality control,
and tested under simulated mission conditions to assure reliability.10 The measures taken to ensure
reliability and safety contributed to the fact that manned spacecraft
invariably tended to grow heavier as they matured, making weight control
a continuing worry.

Those constraints were not so vital in the unmanned programs.
Instruments needed no life-support systems and required no protection
from reentry heat; scientific satellites were usually expendable. Being
smaller than manned spacecraft, they required smaller and less expensive
launch vehicles. Furthermore, those vehicles could be less reliable.
More science could be produced for the money if experimenters would
accept less than 100-percent success in launches, and space scientists
were content with this.11 The loss of a
scientific payload, though serious to the investigators whose
instruments were aboard, did not cost a life.

On the whole the engineers were content to go their way while the
scientists went theirs. But the scientists were not [see Chapter 1], and their protests seemed to
require a response. Manned space flight enthusiasts spoke of the
superiority of humans as scientific investigators and of the benefits to
science that would result from putting trained crews in space or on the
moon to make scientific observations. No existing instrument, they said,
could approach a human's innate ability to react to unexpected
observations and change a preplanned experimental program; if such an
instrument could be built, it would be far more expensive than putting
people into space.12

This argument did not move the space scientists, most of whom worked in
disciplines where human senses were useless in gathering the primary
scientific data. The role of a person in space science was not to make
the observations but to conceive the experiment, design the instruments
to carry it out, and interpret the results.13 Cleverness in these aspects of investigation
was the mark of eminence in scientific research. The early manned
programs offered space scientists no opportunities that could not be
provided more cheaply by the unmanned programs. The relationship between
the manned and unmanned programs - essentially one of independence -
took quite a different turn with the Apollo decision. Within two weeks
of President Kennedy's proposal to Congress, NASA Deputy Administrator
Hugh L. Dryden told the Senate space committee that Apollo planners
would have to draw heavily on the unmanned lunar programs for
information about the lunar surface. Knowledge of lunar topography and
the physical characteristics of the surface layer was vital to the
design of a lunar landing craft. Ranger was the only active project that
could obtain this information, and to provide it, NASA asked Congress
for funds to support four additional Ranger missions. The day after
Dryden testified, NASA Headquarters directed the Jet Propulsion
Laboratory to examine how to reorient Ranger to satisfy Apollo's
needs.14

This directive was received with mixed feelings by the participants in
Ranger. JPL's project managers favored a narrower focus, because the
scientific experiments were giving them technical headaches that
threatened project schedules. They proposed to equip the four new
Rangers with high-resolution television cameras and to leave off the
science experiments, using the payload space to add systems that would
improve the reliability of the spacecraft. Scientists who had
experiments on the Ranger spacecraft, however, were upset by the
proposed change. When they complained to Newell, he and his Lunar and
Planetary Programs director reasserted the primacy of science in Ranger
and did everything they could to keep the experiments on all the
flights. But the difficulties with the Ranger hardware and the pressure
of schedules proved too much. In the end, the problem-plagued Ranger
carried no space science experiments on its successful flights, but did
return photographs showing lunar craters and surface debris less than a
meter* across.15

Apollo could command enough influence to affect the unmanned lunar
programs, but science had no such leverage on manned flights. For that
matter, scientists had little interest in Mercury; its cramped
spacecraft and severe weight limits, plus the short duration of its
flights, made it unattractive to most experimenters. Still, the Mercury
astronauts conducted a few scientific exercises, mostly visual and
photographic observations of astronomical phenomena.16 Comparatively unimportant in themselves, these
experiments pointed up the need for close coordination between the
scientists (and the Office of Space Sciences) and the manned space
flight engineers. After John Glenn's first three-orbit flight on
February 28, 1962, the Office of Space Sciences and the Office of Manned
Space Flight began to look toward the moon and what humans should and
could do there.17

Apollo managers had spent the second half of 1961 making the critical
decisions about launch vehicle and spacecraft design; in the spring of
1962 they were wrestling with the question of mission mode. Should they
plan to go directly from earth to the moon, landing the whole crew along
with the return vehicle and all its fuel on the lunar surface? Or would
it be better to assemble the lunar vehicle in earth orbit - which would
require smaller launch vehicles but would entail closely spaced multiple
launches, rendezvous of spacecraft and lunar rocket, and the unexplored
problems of transferring fuel in zero gravity from earth-orbiting
tankers to the lunar booster? Or was the third possible method,
lunar-orbit rendezvous, preferable: building a separate landing craft to
descend from lunar orbit to the moon, leaving the earth-return vehicle
circling the moon to await their return?18 Apart from its essential impact on the booster
rocket and spacecraft, the mission mode would determine how much
scientific equipment could be landed on the moon, how many men would
land to deploy and operate it, and how long they would be able to stay.
Until the decision was made it was pointless to try to design equipment,
but by early 1962 the mission planners needed to know in general terms
what the scientists hoped to do on the moon and some important questions
of responsibility and authority had to be settled.

* Ranger's results came too late
(1964-1966) to affect the design of the Apollo lunar module; they did
confirm that the designers' assumptions about the lunar surface were
satisfactory and that the lunar module needed no modification.

10. For a discussion of some of the
problems faced by the engineers in ensuring reliability, see Loyd S.
Swenson, Jr., James M. Grimwood, and Charles C. Alexander, This
New Ocean: A History of Project Mercury, NASA SP-4201
(Washington, 1966), pp. 167-213.